I have a 1957 Pontiac Chiften 2 dr it runs and drives with 69257miles whats it worth?

I have original engine and tranny reverse went out less then 1000 miles ago and i couldnt find some 1 to fix tranny so i put a 350 motor and 400 transmission so the car has original 69257 miles on it and the engine is a rebuild with less then 500 miles on it as i said it runs and drives

with limited photos supplied in the cars present condition its probably a 6,000 - 10,000 ride derpending upon interior condition and body rot -- however with original motor and trans and full restoration could easily be worth 40,000 +++ the sky is the limit with original motor and trans for a properly restored 57 that is solid